Urine Calcium, Random
Calcium measured in one urine sample. It depends on how dilute your urine is, so it is usually read as a ratio to creatinine or by a 24-hour test.
AI-verified against cited sources. Awaiting expert reviewLOINC 17862-4
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What it is
This test measures how much calcium is in a single urine sample. Calcium is a mineral your body needs for bones, nerves and muscles, and your kidneys release a small amount in urine every day. Because a single sample can be watery or concentrated, the number alone is hard to interpret. Labs often pair it with creatinine to make a ratio, or ask for a 24-hour collection.
Why it matters
Urine calcium helps clinicians look into kidney stones, parathyroid problems and bone disease, because most kidney stones contain calcium and the parathyroid hormone controls how much calcium your kidneys keep. A single concentration is a rough snapshot. Mayo Clinic Laboratories uses it only as part of the calcium-to-creatinine ratio, and ARUP lists its intervals for the 24-hour amount and the ratio. If your clinician needs a firm answer about calcium loss, a ratio or a 24-hour test is usually the next step.
If it’s low
A lower concentration can mean less calcium was passing out in the urine, or it can simply mean the urine was dilute. Low calcium intake, poor absorption from food and a few hormone or kidney conditions can all lower it.
Common causes
- Dilute urine, for example after drinking a lot of fluid
- Eating little calcium
- Conditions that make it hard to absorb nutrients from food
- Thiazide diuretics, a type of water pill
- Underactive parathyroid glands (hypoparathyroidism), low vitamin D or kidney disease
- Familial hypocalciuric hypercalcemia, an inherited condition that raises blood calcium but usually keeps urine calcium low
What can help
- Ask whether a calcium-to-creatinine ratio or a 24-hour urine collection would give a clearer answer
- Ask whether blood calcium, vitamin D or PTH tests would help
If it’s high
A higher concentration can mean more calcium was passing out in the urine, or it can simply mean the urine was concentrated. Your clinician will usually look at the ratio to creatinine or a 24-hour collection before drawing any conclusion.
Common causes
- Concentrated urine, for example when you haven't had much to drink
- A diet high in salt (sodium) or animal protein
- Calcium supplements, too much vitamin D, or calcium-based antacids
- Loop diuretics, a type of water pill
- Overactive parathyroid glands (hyperparathyroidism)
- Sarcoidosis or some bone conditions
What can help
- Ask whether a calcium-to-creatinine ratio or a 24-hour urine collection would give a clearer answer
- Ask whether your diet, supplements or medicines could be affecting the result
What can affect your result
- How concentrated your urine is (fluids, time of day, heat and exercise)
- Diet, especially salt, protein and calcium
- Calcium and vitamin D supplements, antacids and diuretics
- Parathyroid hormone, vitamin D and kidney function
- How much water is in your urine changes the concentration. Dilute urine reads lower and concentrated urine reads higher, with the same total calcium loss.
- What you eat and drink around the sample matters, especially salt (sodium), protein and calcium.
- Calcium or vitamin D supplements, calcium-based antacids and diuretics can change the result.
A random (spot) urine sample at any time, unless your clinician gives timing instructions. Follow the collection directions you are given. A snapshot of the urine you passed, so it can change from one sample to the next.
When to talk to a clinician
A urine calcium result on its own is not an emergency. Talk with the clinician who ordered it about any result outside your lab's range. See a clinician promptly for sharp pain in your side, back, lower belly or groin, blood in your urine, pain when you urinate, or fever and chills, since these can go with a kidney stone or an infection. Get urgent care if you can't urinate at all or only pass a little.
Questions you could ask
- Could my fluids, diet, supplements or medicines explain this result?
- Should we check my blood calcium or PTH as well?
- Would a calcium-to-creatinine ratio or a 24-hour urine collection help interpret this?
- Would a calcium-to-creatinine ratio or a 24-hour urine collection help interpret this?
Questions people ask
Why doesn't my report show a normal range for urine calcium?
A single urine concentration depends on how dilute your urine is, so it has no widely agreed range. ARUP lists intervals for the 24-hour amount and for the creatinine ratio, and Mayo for the ratio, but neither lists one for the concentration alone. Your clinician may use the ratio or a 24-hour collection instead.
How do I convert mg/dL to mmol/L?
Divide mg/dL by 4.008. For example, 10 mg/dL is about 2.5 mmol/L. To go the other way, multiply mmol/L by 4.008.
Show the science and sources
Units
- 1 mg/dL = 1 mg/dL
- 1 mg/dL = 0.2495 mmol/L
Open the Urine calcium unit converter
For clinicians and researchers
Mayo's CALC5 (photometric, LOINC 17862-4) is orderable only inside the calcium-to-creatinine profile CACR3, where the ratio is calculated, and Mayo publishes age-specific intervals only for the ratio. ARUP reports 'Calcium, Urine - per volume' in mg/dL (component LOINC 35675-8, collected for unspecified duration) with intervals only for the 24-hour amount and the ratio. No stand-alone concentration interval is therefore encoded here. A spot concentration is dominated by urine flow, which is why creatinine correction or a timed collection is preferred (AJKD 2023 calls the 24-hour collection the cornerstone for recurrent stone formers). Convert mmol/L to mg/dL by multiplying by 4.008 (atomic weight 40.08).
LOINC 17862-4 (primary), 35675-8, 2004-0. Specimen: urine.
Sources
- Calcium, Random, Urine (Mayo test CALC5, non-orderable), Mayo Clinic Laboratories
- Calcium/Creatinine Ratio, Random, Urine (Mayo test CACR3), Mayo Clinic Laboratories
- Calcium, Urine (ARUP test 0020472), ARUP Laboratories
- Calcium in Urine Test (MedlinePlus Medical Test), MedlinePlus, U.S. National Library of Medicine
- Calcium - urine (MedlinePlus Medical Encyclopedia), MedlinePlus, U.S. National Library of Medicine (2025)
- Kidney Stone Pathophysiology, Evaluation and Management: Core Curriculum 2023, American Journal of Kidney Diseases (2023)
- Calcium (PubChem compound 5460341), PubChem, U.S. National Library of Medicine
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.